we have performed density functional theory (dft) calculations to investigate the properties of defect in arepresentative armchair model of silicon nanotubes (sints). to this aim, the structures of pristine and defective(5,5) sints have been optimized and the properties such as bond lengths, total energies, binding energies,.formation energies, gap energies, and dipole moments have been evaluat...

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an analytical solution of the equation describing diffusion of intrinsic point defects in semiconductor crystals has been obtained for a one-dimensional finite-length domain with the robin-type boundary conditions. the distributions of point defects for different migration lengths of defects have been calculated. the exact analytical solution was used to verify the approximate numerical solutio...

background: we sought to assess right ventricular (rv) systolic and diastolic functions via tissue doppler imaging (tdi) in order to discriminate right-to-left (bidirectional) from left-to-right intracardiac shunts. methods: a tissue doppler velocity study via doppler echocardiography was performed in 20 patients with left-to-right shunt (without evidence of significant pulmonary hypertension) ...

left ventricular non-compaction cardiomyopathy is a rare congenital cardiomyopathy that affects both children and adults. since the clinical manifestations are not sufficient to establish diagnosis, echocardiography is the diagnostic tool that makes it possible to document ventricular non-compaction and establish prognostic factors. we report a 47-year-old woman with a history of dilated cardio...

background: chylothorax is a rare but serious postoperative condition with a high rate of morbidity and may lead to the mortality of children undergoing congenital heart disease (chd) surgery. this study evaluated the specific surgical procedures associated with the higher risk of postoperative chylothorax. methods: w e assessed 435 cases undergoing chd surgery between april 2003 and may 2006. ...

Wall jets appear in many situations of technological and scientific interest. In gas turbines, flows produced by the film as well impingement cooling devices are three-dimensional wall jets. High-lift produce that can easily be represented two-dimensional It has been known for a long time both stagnant moving environments display layered structure only partially obey similarity laws. this paper...

An acoustic wave pissing through a material has its velocity changed when stress is applied. This is due to changes in the third order elastic constant and the density of the material. By using a small diameter beam or a focused beam Incident on a metal and reflected from both its front and back surfaces, It is possible to measure the difference in phase of the two reflected waves; the beam Its...